Throwing blade connection assembly for abrasive throwing wheel

ABSTRACT

An abrasive throwing wheel assembly includes a runnerhead disposed within a housing and arranged to be rotatably driven about a center rotational axis. The runnerhead includes a plurality of radially extending dovetail shaped channels. In one embodiment, the channels each have a slot extending at an angle relative to a radially extending longitudinal axis of the channel. A throwing blade includes a throwing portion and a dovetail shaped base portion configured to be removably received within one of the plurality of dovetail shaped channels. In one embodiment, the base portion includes a slanted surface configured to extend at a same angle as the slot relative to the radially extending longitudinal axis of the channel when inserted within the channel. A U-shaped locking pin is configured to be received in the slot to prevent radially outward movement of the throwing blade. In another embodiment, the runnerhead channels include an L-shaped slot in a back surface thereof and the base portion of the throwing blade includes a slanted surface and a locking face, the locking face being arranged perpendicular to the slanted surface and substantially parallel to a radially extending longitudinal axis defined by the throwing portion. A substantially L-shaped locking pin is configured to be received in the slot to secure the base portion of the throwing blade within the channel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to and claims the priority benefit of U.S.provisional patent application No. 60/846,352, filed Sep. 22, 2006, theentirety of which is hereby incorporated by reference.

BACKGROUND

1. Field of the Invention

The invention is related to abrasive throwing wheels (blasting machines)used in surface preparation, and more particularly to an improvedthrowing blade connection assembly for such abrasive throwing wheels tosecure throwing blades (vanes) to a runnerhead while allowing removaland replacement of such throwing blades without the need to removeassociated feedparts of the abrasive throwing wheel.

2. Related Art

Centrifugal blasting machines comprising rotors or wheels having aplurality of generally radially extending blades (vanes) installedthereon have been known in the art for many years. When rotated at highspeeds, the blades propel an abrasive material against a work surface.Typical applications for abrasive surface preparation include cleaningof castings, descaling plate, cleaning weldments, shot peening and otherspecial applications. Due to the action of the abrasive material on thethrowing blades, however, the blades can exhibit considerable wear overa period of time. Attempts have been made to fabricate the blades fromabrasion-resistant materials. In other cases, special bladeconfigurations have been employed to minimize the effects of theabrasive material on the blades.

Notwithstanding these attempts to minimize wear and extend the life ofthe throwing blades, the blades must be periodically removed from arunnerhead and replaced. In most centrifugal blast machines, suchperiodic blade removal and replacement requires disassembly of internalfeedparts such as, for example, the feed hose, feed spout, clamps,impeller, and impeller case before removing and replacing the blades.This procedure can be time consuming and often results in a loss ofvaluable operating time. Furthermore, while the blades must beremovable, they must also be held securely enough to resist thetremendous forces exerted on them when the wheel is operating. U.S. Pat.Nos. 4,697,391, 4,249,350, and 2,869,289, and U.S. Patent ApplicationPublication No. 2004-0166777 A1, discuss abrasive throwing wheels havingimproved blade assemblies, and are hereby incorporated by reference intheir entireties.

SUMMARY OF THE INVENTION

Thus, there exists a need for an improved blade assembly for connectingand securing throwing blades to the throwing wheel runnerhead of acentrifugal blasting machine. The throwing blades must be securelymounted on the throwing wheel runnerhead to prevent movement of theblades in operation, especially in a radial outward direction. Theblades should be easily removed and replaced without the need forspecial tools. Furthermore, when the blade is installed in thecentrifugal blasting machine, it should be possible to replace the bladewithout removing the internal feedparts of the blast machine, such asthe impeller or control cage conventionally found in such machines.Additionally, the throwing blades should be securely mounted to therunnerhead without the use of magnets. Many applications may alsorequire a blade having a width of between 2-4″, for example, greaterthan or equal to 3.0″, or a length defining a wheel diameter of, forexample, between 14″ and 17″. Thus, there is a need for an improvedblade assembly that can provide improved support for the blade in therunnerhead, reduce the stresses on the blade during operation, and allowblade replacement or interchangeability without removing the feedparts.

According to one embodiment, an abrasive throwing wheel assembly isprovided. The abrasive throwing wheel assembly includes a housing. Arunnerhead may be disposed within the housing and arranged to berotatably driven by a drive shaft about a center rotational axis. Therunnerhead may include a plurality of radially extending dovetail shapedchannels arranged on a face of the runnerhead. Each channel may includea slot extending at an angle relative to a radially extendinglongitudinal axis of the channel. The abrasive throwing wheel assemblymay further includes a throwing blade. The throwing blade may include athrowing portion and a dovetail shaped base portion configured to beremovably received within one of the plurality of dovetail shapedchannels. The base portion may include a slanted surface configured toextend at a same angle as the slot relative to the radially extendinglongitudinal axis of the channel when inserted within the channel. Theabrasive throwing wheel assembly may further include a U-shaped lockingpin sized and configured to be removably received in the slot to securethe base portion of the throwing blade within the channel. When the baseportion of the throwing blade is received within the channel of therunnerhead and the locking pin is received in the slot, the locking pincontacts the slanted surface to prevent radially outward movement of thethrowing blade.

According to another embodiment, a throwing blade for an abrasivethrowing wheel assembly is provided. The abrasive throwing wheelassembly may include a housing and a runnerhead disposed within thehousing. The runnerhead may be arranged to be rotatably driven by adrive shaft about a center rotational axis and may include a pluralityof radially extending dovetail shaped channels arranged on a face of therunnerhead. Each channel may include a slot extending at an anglerelative to a radially extending longitudinal axis of the channel. Thethrowing blade may include a substantially planar throwing portion and adovetail shaped base portion configured to be removably received withinone of the plurality of dovetail shaped channels of the runnerhead. Thebase portion may include a slanted surface configured to extend at asame angle as the slot relative to the radially extending longitudinalaxis of the channel when inserted within the channel. The slantedsurface may be configured to engage a U-shaped locking pin removablyreceived in the slot whereby the base portion of the throwing blade issecured within the channel.

According to yet another embodiment of the invention, an abrasivethrowing wheel assembly includes a runnerhead disposed within a housingand arranged to be rotatably driven by a drive shaft about a centerrotational axis. The runnerhead may include a plurality of radiallyextending dovetail shaped channels arranged on a face of the runnerhead.Each channel may include an L-shaped slot in a back surface thereofincluding a first portion extending radially and a second portionextending perpendicular to the first portion. The abrasive throwingwheel assembly further includes a throwing blade including a throwingportion and a dovetail shaped base portion configured to be removablyreceived within one of the plurality of dovetail shaped channels of therunnerhead. The base portion may include a slanted surface and a lockingface. The locking face may be arranged perpendicular to the slantedsurface and substantially parallel to a radially extending longitudinalaxis defined by the throwing portion. The abrasive throwing wheelassembly may further include a substantially L-shaped locking pin sizedand configured to be received in the slot to secure the base portion ofthe throwing blade within the channel. The L-shaped locking pin mayinclude a first leg, a second leg, and an angled surface between thefirst and second legs configured to engage the slanted surface of thebase portion. When the base portion of the throwing blade is received inone of the plurality of channels and the second leg of the locking pinis disposed within the second portion of the slot, the angled surface ofthe locking pin contacts the slanted surface of the base portion toprevent radially outward movement of the throwing blade.

According to still another embodiment of the invention, a throwing bladefor an abrasive throwing wheel assembly is provided. The abrasivethrowing wheel assembly may include a runnerhead disposed within ahousing and arranged to be rotatably driven by a drive shaft about acenter rotational axis. The runnerhead may include a plurality ofradially extending dovetail shaped channels arranged on a face of therunnerhead. Each channel may include an L-shaped slot in a back surfacethereof including a first portion extending radially and a secondportion extending perpendicular to the first portion. The throwing blademay include a throwing portion and a dovetail shaped base portionconfigured to be removably received within one of the plurality ofdovetail shaped channels of the runnerhead. The base portion may includea slanted surface and a locking face. The locking face may be arrangedperpendicular to the slanted surface and substantially parallel to aradially extending longitudinal axis defined by the throwing portion.The slanted surface may be configured to engage an angled surface of asubstantially L-shaped locking pin when the base portion is received inthe channel and a leg of the L-shaped locking pin is removably receivedin the second portion of the slot to secure the base portion of thethrowing blade within the channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a detailed cross-sectional side view of an abrasive throwingwheel assembly according to a first embodiment of the invention;

FIG. 2 is a front view of a throwing wheel runnerhead of the abrasivethrowing wheel assembly of FIG. 1;

FIG. 3A is a cross-sectional view of the throwing wheel runnerhead ofFIG. 2 along section 3A-3A;

FIG. 3B is a detailed perspective view of a channel in the throwingwheel runnerhead of FIG. 2;

FIG. 4A is a side view of a throwing blade of the abrasive throwingwheel assembly of FIG. 1;

FIGS. 4B and 4C are top and rear views, respectively, of the throwingblade shown in FIG. 4A;

FIG. 5A is a front view of a lock pin of the abrasive throwing wheelassembly of FIG. 1;

FIGS. 5B and 5C are side and top views, respectively, of the lock pinshown in FIG. 5A;

FIG. 6A is a detailed cross-sectional side view of the abrasive throwingwheel assembly of FIG. 1;

FIG. 6B is a detailed cross-sectional side view of the abrasive throwingwheel assembly of FIG. 1 during removal of a throwing blade;

FIG. 7 is a schematic cross-sectional side view of the abrasive throwingwheel assembly of FIG. 1 during attachment of a throwing blade to therunnerhead;

FIG. 8A is a front view of a throwing wheel runnerhead of an abrasivethrowing wheel assembly according to a second embodiment of theinvention;

FIG. 8B is a cross-sectional view of the throwing wheel runnerhead ofFIG. 8A along section 8B-8B;

FIG. 8C is a partial bottom view of the throwing wheel runnerhead ofFIG. 8A;

FIG. 8D is a partial cross-sectional view of the throwing wheelrunnerhead of FIG. 8A along section 8D-8D;

FIG. 9A is a side view of a throwing blade for attachment to thethrowing wheel runner head of FIG. 8A according to the second embodimentof the invention;

FIGS. 9B and 9C are back and top views, respectively, of the throwingblade of FIG. 9A;

FIG. 10A is a side view of an L-shaped lock pin for use with thethrowing wheel runner head and the throwing blade of FIGS. 8A and 9A,respectively, according to the second embodiment of the invention; and

FIGS. 10B and 10C are front and top views of the L-shaped lock pin ofFIG. 10A.

DETAILED DESCRIPTION

Several embodiments of the invention are discussed in detail below.While specific example embodiments are discussed, it should beunderstood that this is done for illustration purposes only. Indescribing and illustrating the embodiments, specific terminology isemployed for the sake of clarity. However, the invention is not intendedto be limited to the specific terminology so selected. A person skilledin the relevant art will recognize that other components andconfigurations may be used without parting from the spirit and scope ofthe invention. It is to be understood that each specific elementincludes all technical equivalents that operate in a similar manner toaccomplish a similar purpose. Each reference cited herein isincorporated by reference. The examples and embodiments described hereinare non-limiting examples.

The invention is related to an improved throwing blade connectionassembly for abrasive throwing wheels. Exemplary embodiments of thethrowing blade connection assembly secure a throwing blade to thethrowing wheel without bolts or other threaded fasteners and allowremoval and replacement of throwing blades from the throwing wheelrunnerhead without removing the feedparts.

FIGS. 1, 2, 3A-B, 4A-C, 5A-C, 6A-B, and 7 depict an abrasive throwingwheel assembly or blasting machine 10 according to a first embodiment ofthe invention. More particularly, the figures show a first embodiment ofan improved throwing blade connection assembly for such a blastingmachine 10. FIG. 1, for example, depicts a detailed cross-sectional sideview of the blasting machine 10. The blasting machine 10 includes ahousing 11 having a hinged access door D which can be opened or closedas desired for purposes of maintenance and the like. The blastingmachine 10 includes a runnerhead 12 rotatably supported within thehousing 11 by a shaft 14. The shaft 14 is arranged to be driven by amotor M. The runnerhead 12 is connected to the shaft 14 by a hub 16 andbolted fasteners 18. An impeller case 20 is concentrically aligned withthe shaft 14. The impeller case 20 is supported by a portion of thehousing 11 in a stationary position relative to the runnerhead 12 andincludes a radial opening 19. An impeller 13 is coupled to the shaft 14for rotation within the impeller case 20. A feed spout 21 is coupled tothe housing 11 such that abrasive material can be fed through the feedspout 21 and into the housing 11 to the impeller 13.

FIG. 1 shows a plurality of throwing blades 30 (vanes) removably coupledto the runnerhead 12. Each throwing blade 30 includes an abrasivethrowing portion 31 and a base portion 32. In the embodiment depicted inFIGS. 1-7, the base portion 32 has a dovetail shaped cross-section whichis configured to be removably received in a dovetail shaped radialchannel 24 in a face 23 of the runnerhead 12 (see FIG. 2). Each throwingblade 30 is held within the channel 24 by a locking pin 40 which engagesthe base portion 32 of the respective throwing blade 30. A spring 42 isalso disposed within each channel 24 to bias the throwing blade 30 in adirection parallel to the axis of rotation of the runnerhead 12 suchthat the throwing blade 30 is held more securely within the channel 24during operation.

FIGS. 2, 3A, and 3B depict several views of the runnerhead 12 accordingto the embodiment shown in FIG. 1. In the front view of the runnerhead12 shown in FIG. 2, runnerhead 12 includes a face 23 which includes aplurality of radially extending channels 24. Each radially extendingchannel 24 has a dovetail shaped cross-section which is configured toreceive the base portion 32 of one of the throwing blades 30. Althoughthe embodiment shown in FIG. 2 includes eight channels 24, one of skillin the art will recognize that the runnerhead 12 may include any numberof channels 24 equally spaced about the central axis so that therunnerhead 12 is balanced. Each channel 24 includes a back surface 25which is offset from face 23. As shown in FIGS. 2 and 3A, each channel24 includes a slot or recess 26 in back surface 25 which is configuredto receive the locking pin 40. Furthermore, as shown in FIGS. 3A and 3B,each channel 24 may also include a cutaway portion 27 (e.g., aperipheral recess) at a radially outermost portion of the runnerhead 12to facilitate acceptance of the base portion 32 of a respective throwingblade 30 during assembly. As can be seen in FIG. 3A, the slot 26 extendsat an angle to the face 23, wherein the angle is some angle between zeroand 90 degrees such as, for example, 60 degrees, although one ofordinary skill in the art will recognize that other angles may besufficient.

FIGS. 4A-C depict side, rear, and top views, respectively, of thethrowing blade 30 according to the embodiment shown in FIG. 1. Thethrowing blade 30 includes an abrasive material throwing portion 31 anda base portion 32. In the embodiment shown, the throwing portion 31 issubstantially planar such that the throwing blade 30, when mounted tothe runnerhead 12, is essentially bidirectional. That is, the runnerhead12 can rotate clockwise or counterclockwise during operation and thethrowing blade 30 will be effective in throwing the abrasive material.The throwing blade 30 includes a top 36 and bottom 37. The top 36 ispositioned radially outward from the bottom 37 when the throwing blade30 is coupled to the runnerhead 12. The dotted lines at the top 36 ofthe throwing blade 30 depicted in FIGS. 4A-B (see also FIG. 1) areintended to show that the throwing portion 31 of the throwing blade 30may be of various sizes. For example, the throwing portions may be sizedso that the rotational diameter of the throwing blade 30 on therunnerhead 12 is any one of 14″, 15″, 16″, or 17″. Other sizes are alsopossible. The base portion 32 of the throwing blade 30 may be dovetailshaped such that it can be received in the channel 24. The base portion32 includes a surface 33 having a recess 34. The base portion 32 alsoincludes a slanted surface 35.

FIGS. 5A-C depict various views of the locking pin 40. As shown in thedepicted embodiment, the locking pin 40 is substantially U-shaped. ThisU-shaped profile helps during removal and insertion of the pin 40 intothe slot 26 of the runnerhead 12 to effect removal or securement of thethrowing blade 30. The locking pin 40 may have a hole or some otherfeature (not shown) provided at one end thereof to assist with removalby a tool.

FIG. 6A depicts a side cross-sectional view of the blasting machine 10before, during, or after operation. As can be seen in FIG. 6A, thethrowing blades 30 are secured within the channels 24 of the runnerhead12 and cannot move radially outward due to the position of the lockingpin 40 in slot 26. The spring 42 is disposed in recess 34 to stabilizethe throwing blade 30 within the channel 24. During operation of themachine 10, the centrifugal force resulting from the rotation of therunnerhead 12 pulls the blades 30 radially outward such that the slantedsurface 35 of the base portion 32 of throwing blade 30 contacts thelocking pin 40. The bottom 37 of the throwing blade 30 is radiallyspaced from the impeller case 20.

When it becomes time to remove and/or replace one or more of thethrowing blades 30, the access door D (see FIG. 1) is opened, and ablade 30 is removed as shown in FIG. 6B. First, the blade 30 is movedradially inward until the bottom 37 contacts the impeller case 20. Next,the locking pin 40, which is oriented within the slot 26 such that theopen side of the U-shaped body faces outward, is removed. Lastly, thethrowing blade 30 is pulled radially outwardly until the base portion 32is freed from the channel 24 of the runnerhead 12. In order to insert anew throwing blade 30 into the vacated channel 24 of the runnerhead 12,the foregoing steps are performed in reverse order as depicted in FIG.7. None of the elements in FIGS. 1-7 should be magnetized or otherwiseconfigured to include any magnetic elements because the abrasivematerial and the blade 30 are generally made of metal materials whichwould be attracted to a magnetic element. This could potentially preventany one of the elements from seating properly in the runnerhead 12 andthereby cause a failure. If, for example, the blade 30 and/or the pin 40do not seat properly in the runnerhead 12 then the blade 30 can shiftout of the runnerhead 12 and cause the wheel to fail.

Another embodiment of the invention is depicted in FIGS. 8A-D, 9A-C, and10A-C. According to this embodiment, the blasting machine may be thesame as that depicted in FIG. 1, except that the runnerhead, throwingblades, and locking pins have a different construction for addedsecurity in preventing the locking pin from falling out inadvertently.More particularly, in FIG. 8A, a front view of a runnerhead 112 isshown. The runnerhead 112 includes a face 123 which includes a pluralityof radially extending channels 124. Each radially extending channel 124has a dovetail shaped cross-section which is configured to receive thebase portion 132 of one of the throwing blades 130 (see FIGS. 9A-C).Although the embodiment shown in FIG. 8A includes eight channels 124,one of skill in the art will recognize that the runnerhead 112 mayinclude any number of channels 124. Each channel 124 includes a backsurface 125 which is offset from face 123. As shown in FIGS. 8A and 8B,each channel 124 includes a slot or recess 126 in back surface 125 whichis configured to receive a locking pin 140. The slot 126 issubstantially L-shaped and includes a first radially extending portion126 a extending inwardly from an outer peripheral surface of therunnerhead 112. The slot 126 further includes a second tranverse portion126 b which extends substantially perpendicular to the first radiallyextending portion 126 a. The first radially extending portion 126 aextends parallel to a central longitudinal axis (not shown) defined bychannel 124 but is offset from such radially extending central axis.

FIGS. 9A-C depict various views of the throwing blade 130 according tothe second embodiment of the invention. As shown in FIG. 9A, thethrowing blade 130 includes an abrasive material throwing portion 131and a base portion 132. In the embodiment shown, the throwing portion131 is substantially planar such that the throwing blade 130, whenmounted to the runnerhead 112, is essentially bidirectional. That is,the runnerhead 112 can rotate clockwise or counterclockwise duringoperation and the throwing blade 130 will be effective in throwing theabrasive material. The throwing blade 130 includes a top 136 and bottom137. The top 136 is positioned radially outward from the bottom 137 whenthe throwing blade 130 is coupled to the runnerhead 112. The dottedlines at the top 136 of the throwing blade 130 depicted in FIGS. 9A-Bare intended to show that the throwing portion 131 of the throwing blade130 may be of various sizes. For example, the throwing portions may besized so that the rotational diameter of the throwing blade 130 on therunnerhead 112 is any one of 14″, 15″, 16″, or 17″. Other sizes arepossible. The base portion 132 of the throwing blade 130 is dovetailshaped such that it can be received in the channel 124 of the runnerhead112. The base portion 132 includes a surface 133 having a recess 134 forreceiving a spring (not shown). The base portion 132 also includes aslanted surface 135 bordered on one side by a locking face 138. Thelocking face 138 lies in a plane substantially perpendicular to a planedefined by the slanted surface 135 and which is substantially parallelto a longitudinal axis of the throwing blade 130 extending between inthe bottom 137 and top 136 of the throwing blade 130 (see FIGS. 9B and9C).

FIGS. 10A-C depict various views of a locking pin 140. As shown in thedepicted embodiment, the locking pin 140 is substantially L-shaped andincludes a first portion 141 and a second portion 142. This L-shapedprofile helps to secure the throwing blade 130 within the channel 124 byensuring that the pin 140 will not inadvertently fall out of position inthe slot 126. As shown in FIG. 10A, the locking pin 140 includes severalperipheral surfaces including surfaces 143, 144, and 145. Surfaces 143and 145 are disposed at a right angle with respect to one another anddefine part of the first portion 141 of the locking pin 140. Surface144, however, is shown as being at an angle of approximately 30 degreeswith respect to surface 143. Other angles may be possible so long as theangle between surfaces 144 and 143 is substantially the same as theangle between surfaces 133 and 135 on the throwing blade 130. Thelocking pin 140 may also include a through hole 146 on the secondportion 142 to help with removal and insertion of the pin 140 into theslot 126 in the runnerhead 112.

In order to secure the throwing blade 130 to the runnerhead 112, thedovetail shaped base portion 132 of the throwing blade 130 is insertedinto the radially extending channel 124 and moved radially inward untilthe bottom 137 of the throwing blade 130 contacts the impeller case (seeFIG. 1). The locking pin 140 is then inserted into the first radiallyextending portion 126 a of the slot 126 in channel 124. The orientationof the locking pin 140 is such that surface 143 faces the back surface125 of the channel 124, and the surface 144 faces away from the backsurface 125. The surface 145 of the locking pin faces radially outwardfrom the center rotational axis of the runnerhead 112. The locking pin140 is pushed radially inward along first slot portion 126 a and thentransversely so that the first portion 141 of the locking pin 140 isdisposed within transverse portion 126 b of the slot 126. The throwingblade 130 is then moved radially outward until slanted surface 135contacts surface 144 of the locking pin 140. Surface 145 of the lockingpin 140 opposes surface 152 (see FIG. 8A) of the transverse portion 126b of the slot 126 and, consequently, the locking pin 140 and throwingblade 130 are prevented from further radially outward movement.Additionally, the locking face 138 of the throwing blade 130 ispositioned such that it prevents any transverse movement of the lockingpin 140 to a position within first portion 126 a of the slot 126 whereremoval of the locking pin 140 from the slot 126 would otherwise bepossible. In this way, the throwing blade 130 is effectively secured tothe runnerhead 112 within the channel 124. Removal of the throwing blade130 can be achieved by repeating the foregoing steps in reverse orderbeginning with moving the throwing blade 130 radially inward.

In the above-described embodiments, the throwing blades may bebi-directional and may have a width of between approximately 2-4 inchesas defined in a direction extending parallel to the rotational axis ofthe runnerhead when mounted thereon. Other widths may also be possibledepending on the dimensions of the housing. The housing may beconfigured such that throwing wheels having blades of various sizes canbe housed therein. For example, the housing may be configured toaccommodate runnerheads having blades with widths of between 2 to 4inches attached thereto. The housing may also be configured toaccommodate runnerheads having blades mounted thereon that definerotational diameters of between approximately 14 to 17 inches. One ofskill in the art will recognize that blades having other dimensionsand/or which are not bidirectional may also be possible.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of the present invention shouldnot be limited by any of the above-described embodiments, but shouldinstead be defined only in accordance with the following claims andtheir equivalents.

1. An abrasive throwing wheel assembly, comprising: a housing; arunnerhead disposed within the housing and arranged to be rotatablydriven by a drive shaft about a center rotational axis, wherein therunnerhead comprises a plurality of radially extending dovetail shapedchannels arranged on a face of the runnerhead, each channel including aslot extending at an angle relative to a radially extending longitudinalaxis of the channel; a throwing blade including a throwing portion and adovetail shaped base portion configured to be removably received withinone of the plurality of dovetail shaped channels, wherein the baseportion includes a slanted surface configured to extend at a same angleas the slot relative to the radially extending longitudinal axis of thechannel when inserted within the channel; and a U-shaped locking pinsized and configured to be removably received in the slot to secure thebase portion of the throwing blade within the channel, wherein when thebase portion of the throwing blade is received within the channel of therunnerhead and the locking pin is received in the slot, the locking pincontacts the slanted surface to prevent radially outward movement of thethrowing blade.
 2. The abrasive throwing wheel assembly according toclaim 1, further comprising an access door hingedly attached to thehousing so as to be moveable between an open position whereby thethrowing blade can be attached to or removed from the runnerhead and aclosed position whereby the abrasive throwing wheel assembly canoperate.
 3. The abrasive throwing wheel assembly according to claim 1,wherein the channels include at least one peripheral recess at aradially outermost portion of the channel to facilitate receiving thebase portion of the throwing blade during assembly.
 4. The abrasivethrowing wheel assembly according to claim 1, wherein the number ofchannels on the runnerhead is eight.
 5. The abrasive throwing wheelassembly according to claim 1, wherein the angle at which the slotextends relative to radially extending longitudinal axis of the channelis approximately 30 degrees.
 6. The abrasive throwing wheel assemblyaccording to claim 1, wherein the substantially planar throwing portionof the throwing blade defines a length between a bottom and a top, andwherein the length defines a rotational diameter of between about 14 and17 inches when the throwing blade is attached to the runnerhead.
 7. Theabrasive throwing wheel assembly according to claim 6, wherein thesubstantially planar throwing portion of the throwing blade defines awidth of between about 2 and 4 inches.
 8. The abrasive throwing wheelassembly according to claim 1, wherein no portion of the abrasivethrowing wheel assembly includes a magnet or is magnetized.
 9. Theabrasive throwing wheel assembly according to claim 1, wherein thethrowing portion of the throwing blade is substantially planar.
 10. Athrowing blade for an abrasive throwing wheel assembly having a housingand a runnerhead disposed within the housing, the runnerhead arranged tobe rotatably driven by a drive shaft about a center rotational axis andincluding a plurality of radially extending dovetail shaped channelsarranged on a face of the runnerhead, each channel including a slotextending at an angle relative to a radially extending longitudinal axisof the channel, the throwing blade comprising: a substantially planarthrowing portion; and a dovetail shaped base portion configured to beremovably received within one of the plurality of dovetail shapedchannels of the runnerhead, wherein the base portion includes a slantedsurface configured to extend at a same angle as the slot relative to theradially extending longitudinal axis of the channel when inserted withinthe channel, and wherein the slanted surface is configured to engage aU-shaped locking pin removably received in the slot whereby the baseportion of the throwing blade is secured within the channel.
 11. Anabrasive throwing wheel assembly, comprising: a runnerhead disposedwithin a housing and arranged to be rotatably driven by a drive shaftabout a center rotational axis, wherein the runnerhead comprises aplurality of radially extending dovetail shaped channels arranged on aface of the runnerhead, each channel including an L-shaped slot in aback surface thereof including a first portion extending radially and asecond portion extending perpendicular to the first portion; a throwingblade including: a throwing portion; and a dovetail shaped base portionconfigured to be removably received within one of the plurality ofdovetail shaped channels, wherein the base portion includes a slantedsurface and a locking face, the locking face being arrangedperpendicular to the slanted surface and substantially parallel to aradially extending longitudinal axis defined by the throwing portion;and a substantially L-shaped locking pin sized and configured to bereceived in the slot to secure the base portion of the throwing bladewithin the channel, wherein the L-shaped locking pin includes a firstleg, a second leg, and an angled surface between the first and secondlegs configured to engage the slanted surface of the base portion,wherein when the base portion of the throwing blade is received in oneof the plurality of channels and the second leg of the locking pin isdisposed within the second portion of the slot, the angled surface ofthe locking pin contacts the slanted surface of the base portion toprevent radially outward movement of the throwing blade.
 12. Theabrasive throwing wheel assembly according to claim 11, wherein when theslanted surface of the base portion engages the angled surface of thelocking pin, the locking face of the base portion is positioned toprevent transverse movement of the locking pin into the first radiallyextending portion of the slot.
 13. The abrasive throwing wheel assemblyaccording to claim 11, wherein the number of channels on the runnerheadis eight.
 14. The abrasive throwing wheel assembly according to claim11, wherein the throwing portion of the throwing blade is substantiallyplanar and defines a length between a bottom and a top, and wherein thelength defines a rotational diameter of between about 14 and 17 incheswhen the throwing blade is attached to the runnerhead.
 15. The abrasivethrowing wheel assembly according to claim 14, wherein the substantiallyplanar throwing portion of the throwing blade defines a width of betweenabout 2 and 4 inches.
 16. The abrasive throwing wheel assembly accordingto claim 11, wherein the L-shaped locking pin includes a hole extendingthrough the first leg to facilitate removal of the locking pin from theslot.
 17. A method of attaching the throwing blade to the runnerhead ofthe an abrasive throwing wheel assembly of claim 12, the methodcomprising: inserting the base portion of the throwing blade into thechannel; moving the throwing blade radially inward towards the centerrotational axis; radially inserting the locking pin into the firstportion of the slot, wherein the locking pin is oriented such that thefirst leg extends substantially radially and the second leg extendssubstantially parallel to the center rotational axis such that theangled surface is positioned to engage the slanted surface of the baseportion of the throwing blade; moving the locking pin transversely sothat the second leg of the locking pin is positioned within the secondportion of the slot; and moving the throwing blade radially outward awayfrom the center rotational axis until the slanted surface of the baseportion engages the angled surface of the locking pin.
 18. A throwingblade for an abrasive throwing wheel assembly having a runnerheaddisposed within a housing and arranged to be rotatably driven by a driveshaft about a center rotational axis, the runnerhead including aplurality of radially extending dovetail shaped channels arranged on aface of the runnerhead, each channel including an L-shaped slot in aback surface thereof including a first portion extending radially and asecond portion extending perpendicular to the first portion, thethrowing blade comprising: a throwing portion; and a dovetail shapedbase portion configured to be removably received within one of theplurality of dovetail shaped channels of the runnerhead, wherein thebase portion includes a slanted surface and a locking face, the lockingface being arranged perpendicular to the slanted surface andsubstantially parallel to a radially extending longitudinal axis definedby the throwing portion, and wherein the slanted surface is configuredto engage an angled surface of a substantially L-shaped locking pin whenthe base portion is received in the channel and a leg of the L-shapedlocking pin is removably received in the second portion of the slot tosecure the base portion of the throwing blade within the channel.